primery and secondary memories

7/26/2019 Primery and Secondary Memories

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PRIMERY MEMORY

A primary storage device is a component in your computerthat stores information fora short period of time. A primary storage device should not be confused with a"primary storage drive," which would be a hard drive that holds the operating system

in your computer, like "Local Disk (C!." rimary memory is storage where yourcomputerstores instructions and information

about programs it is currently running. rimary storage is much faster than #econdary $emory, but it cannot be used to

store information in the long term. rimary storage is volatile (unstable!% as soon as the power is turned o&, all of the

information in it is lost.

Examples of Primary Storage Devices

A primary storage device is a component in your computerthat stores information for ashort period of time.

RAM

'A$ is a primary storage Device. 'A$, or random access memory, storesinformation that is being processed.

'A$, also called read/write memory, is like a chalkboard. ou can writenotes, read them, and erase them when you no longer need them.

Processor Cache

)he processor, also known as the C* (central processing unit!, processesinformation on your computer.

+n order to do this, it needs somewhere to store the information, which in thiscase is the "cache memory."

)he cache memory transfers data at fast speeds so it can be processed by thecores in the processor.

)he cache memory holds a lot less space than 'A$, however. or e-ample, aprocessor will usually have around / $0 of cache memory, whereas 'A$ mayhave up to 1 20 .

3owever, the cache memory makes up for that in sheer speed. or instance, 'A$will have a speed of 455 $h6, while the cache memory can operate at /.1 2h6.

Processor Registers

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)he processor registers are the smallest and fastest of all primary storagedevices.

)ypically, they hold around 8/ to 91 bits, which is good enough for very simpleprocesses such as math calculations.

)hey are primarily used by the processor to handle calculations used to operatethe programs.

)he larger processes involving software and operating system :les are handledby the cache memory.

SECONDARY MEMORY

)he last type of memory we brie;y introduce here is called secondary storage or

auxiliary storage. )his is memory outside the main body of the computer where we store programs and

data for future use. #econdary (au-iliary! storage media e-tends the storage capabilities of the

computer. ve separated these into their own category because this media can beeasily removed from the computer and stored elsewhere.

!ypes of Seconary Storage Devices

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#econdary storage is de:ned as a storage medium that is separate from the processor and

holds data even with no power passed to it. An e-ample is a hard drive or an optical drive.

"S# Drives

. A *#0 ;ash drive is a type of ;ash memory storage device integrated with auniversal serial businterface. *sually portable and rewritable, some can hold up to 85520.

$loppy Dis%s

/. loppy disks are a storage medium made of a thin magnetic disk. )hey were widelyused from the ?@5s to the ??5s. #torage capabilities ranged from . $b to /55 $0 onsome versions.

CD&R

8. A CD=' (compact disc= recordable! is an optical secondary storage device invented by#ony and hilips. +t is also known as a


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+f you receive error messages that warn of low virtual memory, you need to either add more

'A$ or increase the si6e of your paging :le so that you can run the programs on your

computer. ll need to increase the minimum

si6e of your paging :le. t reFuire a restart, but if you decrease the si6e, you>ll need to

restart your computer for the changes to take e&ect. t disable

or delete the paging :le.

"NI!S O$ MEMORY

bit (binary digitG! H the value of 5 or

4 bits H byte

5/1 bytes H kilobyte

5/1 kilobytes H megabyte

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5/1 megabytes H gigabyte

5/1 gigabytes H terabyte

5/1 terabytes H petabyte

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primery and secondary memories

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